Underwater Sound Propagation Paths between Perth, Australia, and Bermuda: Theory and Experiment

摘要

Oceanic great circle paths of nearly 180 deg of arc exist between the water just west of Perth, Australia, and Bermuda. Archived sound-speed profiles at eight locations along this path were used, along with bathymetric data, as input to the RAYWAVE ray-tracing program to compute the effective horizontal sound speed and propagation loss over slightly different paths of 19,762.9 km and 19,806.8 km range. The sound speeds thus computed were 1480.9 + or - 0.9 and 1479.8 + or - 0.6 m/s, which compare favorably with the previously measured sound speeds (1484.7 + or - 3.7 and 1481.48 + or - 0.6 m/s, respectively). Propagation loss of 162 dB over this propagation path is effectively modeled by assuming spherical spreading out a range of 10 nautical miles and semispherical spreading (15 log r) beyond, plus attenuation of 1.75 dB per 500 nautical miles. The RAYWAVE propagation loss prediction, after adjustment of the propagation path around Crozet Island, is 156 dB in the 10- to 50-Hz band. (Author)